Zeolites are crystalline aluminosilicate compositions which are microporous and which are formed from corner sharing AlO2 and SiO2 tetrahedra. Numerous zeolites, both naturally occurring and synthetically prepared are used in various industrial processes. Synthetic zeolites are prepared via hydrothermal synthesis employing suitable sources of Si, Al and structure directing agents such as alkali metals, alkaline earth metals, amines, or organoammonium cations. The structure directing agents reside in the pores of the zeolite and are largely responsible for the particular structure that is ultimately formed. These species balance the framework charge associated with aluminum and can also serve as space fillers. Zeolites are characterized by having pore openings of uniform dimensions, having a significant ion exchange capacity, and being capable of reversibly desorbing an adsorbed phase which is dispersed throughout the internal voids of the crystal without significantly displacing any atoms which make up the permanent zeolite crystal structure. Zeolites can be used as catalysts for hydrocarbon conversion reactions, which can take place on outside surfaces as well as on internal surfaces within the pore.
One particular zeolite, designated UZM-22, was first disclosed by Miller in 2010, see U.S. Pat. No. 7,744,850. This patent describes the synthesis of UZM-22 from a choline structure directing agent in combination with either Li, Sr, or both cations, using the Charge Density Mismatch (CDM) approach to zeolite synthesis as described in U.S. Pat. No. 7,578,993. The UZM-22 zeolite has the MEI structure as defined by Database of Zeolite Structures, http://www.iza-structure.org/databases, which consists of 1-dimensional 12-ring pores with a 7 Å aperture, along with a perpendicular 7-ring pore system. This promising result inspired further work with the choline structure directing agent along with various combinations of alkali and alkaline earth cations, using the CDM approach along with combinatorial high throughput synthesis methods. The screen of the choline-alkali-alkaline earth aluminosilicates yielded many known zeolite structures, including OFF, ERI, LTL, FAU, FER, LTA, CHA, BPH, MEI, and others. Several new zeolite structures were also observed, including UZM-7, which is the subject of present invention.
The applicants have successfully prepared a new family of materials designated UZM-7. The topology of UZM-7 is unique as determined by x-ray diffraction. The diffraction peaks for the UZM-7 materials are typically very broad, indicative of a small crystallite material. The materials are prepared via the use of a simple commercially available structure directing agents, such as choline hydroxide, [HO(CH2)2NMe3]+OH−, in concert with small amounts of Ba2+ and Li+ together, using the CDM approach to zeolite synthesis.